One-Pot Synthesis of MoS₂/WS₂ Heterostructures by Chemical Vapor Deposition

The assembly of two dimensional (2D) materials into van der Waals heterostructures has emerged as a new approach for engineering novel materials with tailored functionalities. Among transition metal dichalcogenides (TMDs), MoS₂/WS₂ is a type-II heterostructure that exhibits strong photoluminescence (PL) quenching, ultrafast interlayer charge transfer, and tightly bound interlayer excitons. The physical properties of MoS₂/ WS₂ heterostructures make it a promising candidate for photodetectors, light-emitting diodes, and thermoelectric devices, but the synthesis-assemble method can introduce contamination and twist variability. In this work, we synthesized the MoS₂/ WS₂ heterostructures via two methods: a solution-based spin coating technique and a single step powder-based chemical vapor deposition (CVD) process. Both approaches yield heterostructures with AB stacking. Raman spectroscopy confirms the presence of characteristic E’ and A₁’ modes for both MoS₂ and WS₂ in the heterostructure region. Significant photoluminescence (PL) quenching is observed. At 80K, a new PL peak emerges at approximately 1.92 eV, and all peaks exhibit a shift to lower energy. The observation of layer breathing mode (LBM) and shear mode (SM) further characterizes the interlayer interactions within the heterostructure. Atomic force microscopy confirms the monolayer nature. The work provides a universal, scalable, transfer-free, and one-pot pathway to the synthesis of heterostructures.